The present invention relates to apparatus for producing and processing a homogenized layer of fibrous particles, particularly to improvements in distributors for use in cigarette rod making machines or the like. Still more particularly, the invention relates to improvements in treatment of shredded tobacco or analogous fibrous material prior to and during conversion of a supply (e.g., a column) of such material into a continuous layer, e.g., into a layer adapted to be converted into a narrow tabacco stream which is ready to be trimmed (if necessary) and draped into a web of cigarette paper or the like to form therewith a continuous rod wherein a tubular wrapper surrounds a rod-like tobacco filler.
Satisfactory homogenization of a layer of natural or reconstituted tabacco particles which are to form the filler of a continuous cigarette rod is highly desirable for a number of reasons. Thus, uniform distribution of shorter and longer tobacco shreds in the filler of a cigarette rod contributes to uniformity of the weight of discrete cigarettes and reduces the likelihood of escape of tobacco particles at the tobacco-containing ends of a plain cigarette or at the tobacco-containing end of a filter cigarette. As a rule, the weight of cigarettes and other rod-shaped smokers' products must match, or is permitted to deviate only negligibly from, a predetermined norm. Also, the tobacco-containing ends of cigarettes are tested prior to packing, and the cigarettes having unsatisfactory tobacco containing ends are segregated from acceptable cigarettes so that absence of homogenization of the layer which is converted into a rod-like filler invariably results in an excessive number of rejects. The distributor of a cigarette rod making machine normally comprises a conveyor which withdraws an unequalized layer of tobacco particles from a relatively large supply or mass of such particles, and the layer is thereupon transported past several stations which include brushes, rollers, drums, endless belt conveyors and like equalizing and homogenizing components which uniformize the layer prior to admission of its particles into the tabacco stream forming zone, e.g., into an elongated channel wherein a shower of tabacco particles is converted into a narrow stream. The aforementioned homogenizing components invariably produce a relatively high percentage of short tobacco and tobacco dust which is likely to be segregated from longer particles to form unsatisfactory sections of the stream.
German printed publication No. 1,782,380 discloses a distributor wherein a drum withdraws tobacco particles from a duct and showers the withdrawn particles onto an endless band conveyor. The distributor further includes means for weighing the quantity of showered tobacco particles per unit of time and for transmitting signals which are utilized to regulate the speed of the drum for the purpose of maintaining the weight of withdrawn particles within a predetermined range. Such distributors constitute an improvement over other conventional distributors; however, their cost is rather high, especially in view of relatively small improvements in the quality of the filler.